Polymeric materials with grafted luminescent organosiloxane coatings

A procedure was developed for preparing polymeric materials with grafted luminescence organosiloxane coatings containing conjugates of rare-earth elements with various color spectra.     

Physicochemical properties of complexing para-substituted polystyrene sorbents containing functional amino groups

The acid-base properties of the analytical functional groups of complexing polymer sorbents based on aminopolystyrene and the sorption capacity of the sorbents were investigated. The influence of various substituents on the acid-base properties of the sorbents was studied.     

Structure and properties of nanosized coatings deposited onto polymers

Results of studies aimed at developing a new approach to measuring stress-strain properties of nanosized solids (strength, yield stress, and the value of plastic deformation at uniaxial tension) are generalized. This approach is based on the analysis of the parameters of microrelief arising upon the deformation of polymer films with thin coatings. It is demonstrated for the first time that the stress-strain properties of aluminum coatings deposited onto Lavsan substrates depend on the level of stresses in the substrate, the value of its deformation, and the thickness of the coating. The evolution of these parameters is related to the strain hardening of metal and the effect of nanostructuring of crystalline materials in the range of small thicknesses. When precious metal (Au, Pt) nanosized films are deposited onto polymers by ion-plasma sputtering, in the course of metal deposition, polymer surface layers interact with cold plasma. Stress-strain properties of polymer surface layers modified by plasma are quantitatively estimated for the first time. The model is proposed that makes it possible to take into account the contribution of the properties of precious metal and plasma-modified polymer surface layer to the strength of the coating.     

Preparation and properties of sorbents based on silica gel containing covalently linked fullerene C60

Sorbents containing 10–12 % fullerene C₆₀ were prepared by the reaction of C₆₀ with -aminopropylsilica gel. C₆₀-Silica gel possesses good chromatographic properties for the separation of aromatic, nitro, and heterocyclic compounds in the regimes of normal and reversed-phase HPLC.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 814–816, April, 1996.     

Acidic and basic properties of the surface of gas-chromatographic sorbents with grafted metal chelate layers

The acidic and basic properties of the surface of gas-chromatographic sorbents based on silica gels with grafted layers of nickel acetylacetonate and nickel-malonic and acetoacetic esters were studied by pH measurements and the Hammett indicators adsorption method. The acidic and basic state of the surface was shown to depend on the ligand of the modifying addition, the structure of the complex, and the structural and sorption properties of the silica gels used.     

Synthesis of chitosan-mineral sorbents on fibrous supports and study of their properties

Mechanoacoustic method was used to obtain ultrafine suspensions based on chitosan solutions and inorganic fillers. The rheological properties of the resulting suspensions, their finishing capacity for linen materials, and sorption capacity for copper ions of the fibrous sorbents obtained were examined.     

Preparation,crystal structures and properties of half-sandwich ruthenium complexes containing salicylbenzoxazole ligands

Three half-sandwich ruthenium complexes [Ru(p-cymene)LCl] containing salicylbenzoxazole ligands [LH = 2-(5-methyl-benzoxazol-2-yl)-4-methyl-phenol (2a), LH = 2-(5-methyl-benzoxazol-2-yl)-4-chloro-phenol (2b), and LH = 2-(5-methyl-benzoxazol-2-yl)-4-bromo-phenol (2c)] were synthesized and characterized. All half-sandwich ruthenium complexes were fully characterized by ¹H and ¹³C NMR spectra, MS, elemental analyses, and UV–vis as well as cyclic voltammetry (CV). The molecular structures of 2a, 2b, and 2c were confirmed by single-crystal X-ray diffraction. Single-crystal X-ray structures show that the synthesized ruthenium complexes are three-legged piano-stools with a six-membered metallocycle formed by coordination of the bidentate salicylbenzoxazole ligands to the metal centers. Data from CV and UV–vis absorption of the ruthenium complexes indicated that by changing the substituent on the para position of (donating or withdraw group) the salicylbenzoxazole ligands, minor changes in redox and electronic properties of the ruthenium complexes were observed.     

Adsorption properties of silica-based sorbents containing phosphonic acid residues

Isotherms are measured for nitrogen, n-hexane, triethylamine, and water vapor adsorption on silicas of different origins, the surface layers of which contain functional groups of the ??Si(CH₂)₂P(O)(OH)₂ composition, namely, ethylene- and phenylene-bridged polysilsesquioxane xerogels produced by the sol-gel method, silica microspheres synthesized from tetraethoxysilane in the presence of [CH₃(CH₂)₁₇N(CH₃)₃]Br as a template by spray-drying method, and SBA-15 mesoporous silica produced based on tetraethoxysilane using Pluronic 123 as a template. It is shown that all of the samples possess high specific surface areas, while the types of adsorption isotherms and the accessibility of active acidic sites for adsorption interactions with electron-donor molecules depend on the structures of pores and surface layers, which are governed by the methods of synthesis and postsynthesis sample treatment.     

Possible insights into metal ion recognition in calcium-binding proteins provided by complexing properties of ligands containing amide oxygen donors

The formation constants of the ligand N,N,N',N'-tetrakis(carbamoylmethyl)-ethylenediamine suggest that the amide oxygen is a stronger Lewis base in water than the alcoholic oxygen, or water, and that part of the selectivity for Ca2+ over Mg2+ shown by calcium-binding proteins such as calmodulin or annexin may be due to the higher affinity of Ca2+ for the O-donor of the Ca-binding amide groups present in such proteins.     

Preparation and characterization of affinity sorbents based on isoalloxazine-like ligands for separation of flavoenzymes

Affinity ligands for flavoenzymes were synthesized based on the natural structure of flavo-coenzymes. Two typical flavoenzymes, cholesterol oxidase from Brevibacterium sp. and xanthine oxidase from bovine milk, were employed as standard enzymes. Fluorescent probes were synthesized from eight isoalloxazine-like chemicals and 5-aminofluorescein. Probe-enzyme interactions were analyzed via fluorescence spectra. Chemicals with high binding abilities to flavoenzymes were coupled with Sepharose through spacers composed of epichlorohydrin, ethylenediamine, 1,3-diaminopropane, 2-hydroxy-1,3-diaminopropane, and 1,4-diaminobutane, and subjected to adsorption analysis with flavoenzymes. The results indicated that ligands synthesized from 2,4-dioxohexahydropyrimidine-5-carboxylic acid, cytosine, 7-chloroalloxazine, and 8-chloroalloxazine had high binding abilities to the flavoenzymes. The affinity sorbent based on these ligands revealed a high theoretical maximum adsorption (Q(max)). Protein and bioactivity recoveries were tested after one step of affinity binding via chromatographic analysis on small columns. Results showed that ligands linked with sorbents through long hydrophilic spacers had higher activity recoveries.     

Synthesis and metal cation complexing properties of crown-annelated terthiophenes containing 3,4-ethylenedioxythiophene

Macrocyclic systems derived from crown-annelated terthiophene involving a median EDOT unit have been synthesized by coupling diiodooligooxyethylene chains and bis(2-cyanoethylsulfanyl)terthiophene under high dilution conditions. The metal cation complexing properties of the compounds have been analyzed using 1H NMR, UV-vis spectroscopy, and cyclic voltammetry. These various experiments provide consistent results showing that one of the compounds exhibits interesting complexing properties for Pb2+.     

Preparation and properties of diphenyliron and phenylcobalt complexes with triethylphosphine ligands

Summary New phenyl complexes, FePh₂(PEt₃)₂ (1) and CoPh(acac)(PEt₃)₂ (2), were prepared by the reactions of [M(acac)₃] (M = he and Co, respectively) with AIPh₃ · Et₂O in the presence of PEt₃. Complex (1) is thermally unstable and decomposes above 0°, whereas the more stable complex (2) has m.p. 66–68°. Complexes (1) and (2) were characterized by means of microanalyses, i.r. spectroscopy, and some chemical reactions. Complex (1) reacted with carbon monoxide to give a high yield of benzophenone, while (2) gave only a small amount of cobaltcarbonyl species on reaction with carbon monoxide.     

Preparation and characterization of polyfluoroaniline/organosiloxane hybrid films

Polyfluoroaniline (PFANI)/organosiloxane hybrid films were directly prepared from PFANI emulsions and γ-glycidoxypropyltrimethoxysilane (GPTMS) through a sol–gel method. The influence of GPTMS/FANI molar ratios on the morphology and properties of PFANI/GPTMS hybrid films was characterized by fourier-transform infrared, scanning electron microscopy, thermo gravimetric, contact angle measurement and potentiodynamic polarization analysis. It was found that the hybrid films are highly water repellent. In addition, increasing the GPTMS content could significantly improve the thermal behavior and corrosion resistant ability of the hybrid films. However, the water repellency decreases slowly as the GPTMS/FANI molar ratio increases.     

Preparation and properties of POSS grafted polypropylene by reactive blending

The octavinyl polyhedral oligomeric silsesquioxane (POSS) grafted polypropylene (PP) was first prepared by reactive blending. The structure and properties of physical blending and reactive blending composites of PP/POSS were investigated by wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA). WAXD analysis shows that the POSS in the reactive blending composites has better compatibility with PP than in the physical blending composites. The β-form crystalline hence disappears even the non-reactive POSS can act as an effective β-nucleating agents. DSC analysis shows the reactive blending composites have higher crystalline temperature while POSS in the physical blending composites have little effect on the crystalline temperature. The modulus of reactive blending composites increases in the presence of POSS, while that of the physical blending composites decreases with increasing POSS content.